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Full text of "Alaskan glacier studies of the National Geographic Society in the Yakutat Bay, Prince William Sound and lower Copper River regions"

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GLACIERS OF HARRIMAN FIORD AND FORT WELLS          SSI
•was distinctly not of glacial character when we saw it; it had no motion and was more like a talus deposit than anything else.
Moraine and Outwash. A noteworthy feature, giving to Baker Glacier an interest out of proportion to its present size and activity, is the fact that in former times it has been of greater size, descending the mountain slope and spreading out at its base in a bulb, almost exactly as the Vassar Glacier in College Fiord does at present. Evidence of this •expansion is found in the narrow, piedmont coastal plain in front (Fig. 46). This has a total width of 2000 or 3000 feet and is made up of a compound, crescentic moraine, outside which are isolated strips of outwash gravels, while on the inner side is a smaller •area of outwash between the terminal moraine and the foot of the snow fan. The two outer areas of outwash are alluvial fans 1000 and 1400 feet wide lying to the right and left of the terminal moraine, which extends to the fiord between them.
The terminal moraine is spoken of as compound because of the evidence of two stages in its building; but the deposit is essentially one continuous crescentic mass of knobs and ridges, hollows with lakes, and undrained areas. The largest of the lakes is over 1500 ieet long, but all of the others are very small. The local relief is £0 or 25 feet. This moraine is very stony and in places has no trees, but there are many lichens. The larger part of the outer morainic accumulation is densely covered with forest. Near the inner moraine are willows up to 29 years of age and alders as much as SO years old. Farther out are mature thickly-set spruces and hemlocks, including trees with 98 to 110 annual rings. The eastern side of tTn'a outer moraine extends down to Harriman Fiord, but the western side is separated from the fiord by an alluvial fan of older outwash which we associate with the older moraine because of the age of the trees and shrubs upon it. The older outwash fan on the eastern side supports a dense growth of grass, proving that no glacial streams now flow across it; but there is little other vegetation.
The inner part of the terminal moraine extends in a much narrower crescent than the outer. That it was formed in a relatively recent stage of activity of Baker Glacier is proved by the fact that its irregular surface is not thickly moss covered, as the outer moraine is, and none of the scattered willows and alders are more than 17 or 18 years old.
Outwash deposits are still being made, on the lower slopes of the inner moraine, being supplied with water from the glacier and the snow fan. Some of the streams flow directly down the mountains from the eastern edge of the glacier; but several, after emerging from the glacier, flow down over the rock wall for about 200 feet, then disappear beneath the upper edge of the snow fan, emerging at its lower edge. Two large streams flow over the inner area of outwash gravels and across the terminal moraine hillocks in deeply out galleys. Each of these streams is also continuing the building of the outer alluvial fans; but in contrast to the older outwash described above, the gravels now being deposited have no vegetation upon their surface.
Surprise Glacier—Description. The Surprise Glacier (PI. CXXXIV) has a known length of over 4 miles, and a width at the terminus of 8850 feet. Six tributaries are known (PL CXXXV), but since the grade is still low at the most westerly point visible from, the fiord, it seems probable that the glacier is even longer and fed by a still larger number of tributaries. The terminal ice cliff is 272 feet high in the middle, and 214 feet high on the northern margin, while back of it is a terminal cascade with a slope of 1900 to 2800 feet to the mile, above which the grade flattens. The glacier surface,